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Okay, everyone. Strap in. This is going to be long. After 8 1/2 hours of measurements, and over 6 hours of analysis, and writing, I finally ran out of wine.

Tl;Dr:

I am speechless. The HomePod actually sounds better than the KEF X300A. If you’re new to the Audiophile world, KEF is a very well respected and much loved speaker company. I actually deleted my very first measurements and re-checked everything because they were so good, I thought I’d made an error. Apple has managed to extract peak performance from a pint sized speaker, a feat that deserves a standing ovation. The HomePod is 100% an Audiophile grade Speaker.

EDIT: before you read any further, please read /u/edechamps excellent reply to this post and then read this excellent discussion between him and /u/Ilkless about measuring, conventions, some of the mistakes I've made, and how the data should be interpreted. His conclusion, if I'm reading it right, is that these measurements are largely inconclusive, since the measurements were not done in an anechoic chamber. Since I dont have one of those handy, these measurements should be taken with a brick of salt. I still hope that some of the information in here, the discussion, the guesses, and more are useful to everyone. This really is a new type of speaker (again see the discussion) and evaluating it accurately is bloody difficult.

One Last Note: Use the TOC and Ctrl+F to skip around the review. I've included codes that correspond to each section for ease of reading and discussion. For example Ctrl/Cmd+F and "0.0" should take you to the Table of Contents.

1. Introduction

So, it’s time to put the HomePod to the test. Every reviewer thus far has said some amazing things about this diminutive speaker. However, almost no one has done measurements. However, there’s been a ton of interest in proper measurements. If you’re here from the Apple subreddit, Twitter or anywhere else, welcome to /r/Audiophile, Feel free to hang around, ask questions, and more. /u/Arve and /u/Ilkless will be hanging out in the comments, playing around with this data set, and will have more graphs, charts, etc. They'll be helping me answer questions! Feel free to join in the discussion after you read the review.

1.a The Room

All measurements were done in my relatively spartan apartment room. There is no room treatment, the floor is carpet, and the living room where testing was done has dimensions of 11 ft x 13 ft, with an open wall on one side (going to the Kitchen). It’s a tiny apartment I only use it when I’m in town going to classes in this city.

The room is carpeted, but the kitchen has wood flooring. There is one large window in the room, and a partial wall dividing the kitchen and living room. Here’s a tiny floor plan. The HomePod was sitting nearest to the wall that divides the living room and bedroom, as shown. The only furniture in the room is a couch against the far wall, a small table near the couch, the desk, and a lamp.
Here's an actual picture of the setup

Such a small space with no room treatment is a difficult scenario for the audiophile. It's also a great room to test the HomePod in, because I wanted to push Apple's room correction to the limit. The KEFs sitting atop my desk are also meticulously positioned, and have been used in this room for 3 years now. I set them up long ago, as ideally as possible for this room. Therefore, this test represents a meticulously set up audiophile grade speaker versus a Tiny little HomePod that claims to do room correction on its own.

1.b Tools

I’m using a MiniDSP UMIK-1 USB Calibrated Microphone, with the downloaded calibration file matched to the serial number. For those of you who are unfamiliar, a calibrated microphone is a special microphone made for measuring speakers - though many expensive microphones are made to rigorous standards, there are still tiny differences. The calibration file irons out even those differences, allowing you to make exact speaker measurements. Two different calibrated microphones should measure exactly the same, and perfectly flat in their frequency response.

The software I used is the well known Room EQ Wizard, Version 5.18 on macOS 10.13.3 on a 2011 MacBook Pro. Room EQ Wizard is a cross-platform application for doing exactly this kind of thing - measuring speakers, analyzing a room, and EQ'ing the sound of a speaker system.

Tres Picos Borsao - a 2016 Garnacha. A decent and relatively cheap wine from Spain (around $20). Very jammy, with bold fruit tones, and quite heady as well. 15% ABV. Yes, it’s part of the toolkit. Pair some wine with your speakers, and thank me later :)

1.c Methods

The purpose of describing exactly what was done is to allow people to double check my results, or spot errors that I may have made, and then re-do the measurements better. I believe that if you're seeing something, and document how you measured it, others should be able to retrace your steps and get the same result. That's how we make sure everything is accurate.

To keep things fair, I used AirPlay for both speakers. (Apple’s proprietary wireless lossless audio interface). AirPlay is a digital connection which works at 16 bit 44.1Khz. It is what I used to play sound to each speaker. The KEFs X300A’s have an airplay receiver, and so does the HomePod. AirPlay purposely introduces a 2 second delay to all audio, so Room EQ Wizard was told to start measurements when a high frequency spike was heard. The Computer transmitted that spike right before the sweep, and the microphone would start recording data when that initial spike was heard, enabling it to properly time the measurements.

The miniDSP UMIK1 was attached to my MacBook pro, and the playback loop was as follows:
Macbook Pro >> HomePod / KEF X300A >> MiniDSP UMIK1
The UMIK-1 was set atop my swivel chair for easy positioning. I stacked a ton of books and old notes to bring it up to listening height. :)

For the dispersion measurements, since the KEF speaker is sitting on my desk, it was only fair that I leave the HomePod on my desk as well. Both speakers are resting directly on the desk unless otherwise stated. In some HomePod measurements, I made a makeshift stand by stacking books. Is this ideal? Nope. But its more challenging for Apple’s room correction, and more realistic to the use case of the HomePods, and more fair to measure both speakers in the exact same spot on the desk.

I put some tape down on the desk clearly marking 90º, 45º, 30º, 15º, and 0º. Each speaker that was measured was placed in the center of this semicircle, allowing me to move the chair around, line up the mic, measure the distance, and then record a measurement. I was quite precise with the angles and distances, A tape measure to touch the speaker surface, adjust the angle, and line up the mic. The Mic position varied ±2º on any given measurement (variance based on 10 positioning trials). Distance from the speaker varied by ±0.5 inches (1.27cm) or less, per measurement at 5ft, and less than ±0.25 inches (0.64cm) for the 1 ft or 4in near field measurements.

I timed the measurements so that my air conditioning unit was not running, and no other appliances were turned on in the house (no dishwasher, or dryer). Room temperature was 72ºF (22.2ºC) and the humidity outside was 97%. Air Pressure was 30.1 inHg (764.54 mmHg) I highly doubt these conditions will affect sound to a large degree, but there you have it — weather data.

The HomePod is a self calibrating speaker. Interestingly enough, It does not use any tones to calibrate. Instead, it adjusts on the fly based on the the sounds it is playing. Therefore, in order to get accurate measurements, the speaker must play music for 30 seconds as it adapts to the position in the room. If moved, an accelerometer detects the movement and the next time the HomePod plays, it will recalibrate. Therefore, anyone making measurements MUST position the home pod, calibrate it to the position by playing some music, and only then should you send your frequency sweeps. Failing to do this will distort your measurements, as HomePod will be adjusting its frequency response as you’re playing the REW sweep.

2. Measurements and Analysis

2.a Frequency Response

I had to re-measure the frequency response at 100% volume, using a -24 db (rather than a -12 db) sine wave, in order to better see the true frequency response of the speaker. This is because Apple uses Fletcher Munson Loudness Compensation on the HomePod (which we'll get into in a bit)

Keeping the volume at 100% let us tricking the Fletcher Munson curve by locking it into place. Then, we could measure the speaker more directly by sending sine waves generated at different SPL’s, to generate a frequency response curve at various volume levels. This was the only way to measure the HomePod without the Fletcher Munson Curve compensating for the sound. The resultant graph shows the near-perfectly flat frequency response of the HomePod. Another testament to this incredible speaker’s ability to be true to any recording.

Here is that graph, note that it's had 1/12 smoothing applied to it, in order to make it easier to read. As far we can tell, this is the true frequency response of the HomePod.

At 100% volume, 5 feet away from the HomePod, at a 0º angle (right in front) with a -24db Sine Wave. For this measurement the HomePod was on a makeshift stand that’s approximately 5 inches high. The reason for doing this is that when it was left on the desk, there is a 1.5Khz spike in the frequency response due to reflections off the wood. Like any other speaker, The HomePod is susceptible to nearby reflections if placed on a surface, as they happen far too close to the initial sound for any room compensation to take place.

What we can immediately see is that the HomePod has an incredibly flat frequency response at multiple volumes. It doesn’t try to over emphasize the lows, mids, or highs. This is both ideal, and impressive because it allows the HomePod to accurately reproduce audio that’s sent to it. All the way from 40Hz to 20,000Hz it's ±3dB, and from 60Hz to 13.5Khz, it's less than ±1dB... Hold on while I pick my jaw up off the floor.

2.a1 Highs

The highs are exceptionally crisp. Apple has managed to keep the level of distortion on the tweeters (which are actually Balanced Mode Radiators - more on that later) to a remarkably low level. The result is a very smooth frequency response all the way from the crossover (which is somewhere between 200-500Hz) and the Mids and Highs. [The Distortion is stunningly low for Balanced Mode Radiators.] The BMR’s mode transition is very subtle, and occurs just above 3K. This is where the BMR’s start to “ripple” rather than just acting as a simple driver. I'll speak more about BMR's later :)

2.a2 Mids

Vocals are very true-to-life, and again, the frequency response remains incredibly flat. Below 3Khz the BMR’s are acting like simple pistonic drivers, and they remain smooth and quite free of distortion. This continues down to somewhere between 500Hz and 200Hz, where the crossover to the lows is. This is where the balanced Mode Radiators really shine. By lowering the crossover frequency, moving it away from the 1-3Khz range, where typical tweeters are limited, the crossover is much easier to work with from a design perspective.

2.a3 Lows

The control on the bass is impressive. At 100% volume, the woofer tops out at -12db, where you can start to see the control creep in on the very top graph, as the distortion rises with loudness, the excursion is restrained by the internal microphone that’s coupled to the woofer. Despite this being a 4inch subwoofer with 20mm of driver excursion (how far the driver moves during a single impulse), there is no audibly discernible distortion. If you look at This graph of frequency responses at various SPL's you can see how the subwoofer response is even until the -12 db curve at the top, where it starts to slide downward, relative to everything else? that's the subwoofer being reigned in. Apple's got the HomePod competently producing bass down to ~40 Hz, even at 95 dB volumes, and the bottom-end cutoff doesn't seem to be a moving goalpost. Thats incredibly impressive.

It’s also important to note that the woofer is being reigned in to never distort the mids or highs, no matter what is playing. The result is a very pleasing sound.

2.b Distortion

If we look at the Total Harmonic Distortion (THD) at various sound pressure levels (SPLs) we see that Apple begins to “reign in” the woofer when THD approaches 10db below the woofer output. Since decibels are on a log scale, Apple’s limit on the woofer is to restrict excursion when the harmonic distortion approaches HALF the intensity of the primary sound, effectively meaning you will not hear it. What apple has achieved here is incredibly impressive — such tight control on bass from within a speaker is unheard of in the audio industry.

Note the rise in distortion is what causes apple to pull back on the Woofer a bit, as noted in the above sections! :D their woofer control is excellent. Even though Distortion rises for the woofer, it's imperceptible. The (lack of) bass distortion is beyond spectacular, and I honestly don't think there is any bookshelf-sized speaker that doesn't employ computational audio that will beat it right now.

For the tweeters, distortion also stays impressively low. The Balanced Mode Radiators that apple is using are a generation ahead of most BMR's in the industry. Whether this is the work of the onboard DSP, or the driver design, we weren't able to work out. You'd need a destructive teardown of the HomePod and some extensive measurements and analysis before I could tell you for sure, but the end result is stupidly low distortion in the high frequency range. Anything from the 3rd harmonic and above are VERY low from 150Hz to 80Hz.

2.c Room Correction

This apartment room has no room treatment at all. It’s tiny, and the volume of the room is just under 40m3. And as amazing as the measurements above are, It's even more impressive that the HomePod somehow manages an almost perfectly flat speaker response in such a terrible environment. So, not only do we have a little speaker that manages uncharacteristically low distortion, and near-perfect frequency response, but it does so while adapting to the room. The response takes a few minutes of playing music to settle before measurements are stable - indicative of some sort of live DSP correction. Mind you, any audiophile that was getting such good control over a space with lots of room treatment and traditional speakers would be very happy with these measurements. To have this sort of thing be a built in feature of the Digital Signal Processing (DSP) inside the speaker that is, for all intents and purposes omnidirectional, allowing it to adapt to any room, no matter how imperfect, is just beyond impressive. What Apple has managed to do here is so crazy, that If you told me they had chalk, candles, and a pentagram on the floor of their Anechoic chambers, I would believe you. This is witchcraft. I have no other word for it.

2.d Fletcher Munson Curves

The HomePod is using Fletcher-Munson loudness compensation.

What the hell is that, you ask? Fletcher Munson loudness compensation has to do with how humans hear different frequencies at different volumes.

Your ear has different sensitivity to different frequencies, right? If I make a sound at 90Hz and a sound at 5000Hz even if the absolute energy of the two sounds is the same, you will perceive them to be at different loudness, just because your ear is more sensitive to one frequency over another. Speakers account for this by designing their frequency responses around the sensitivity of human hearing. But there’s another problem…

Your perception of different frequencies changes with different absolute energies. So lets say I generated a 60 db tone at 90Hz and 5000Hz, and then a 80db tone at 90Hz and 5000Hz.... Your brain would tell you that EACH of those 4 tones was at a differently louder, compared to the other tone of the same frequency. Check out this doodle where I attempt to explain this. The part circled in yellow is what is being fixed, correcting for the fact that your brain sees a 10db jump at 90Hz differently than a 10db jump at 5000Hz.

The Fletcher-Munson curve, then, defines these changes, and with some digital signal processing based on how high you’ve got the volume cranked, the sound played can be adjusted With Fletcher Munson Compensation. So, going back to our example, The two 90Hz tones and two 5000Hz would sound like they were exactly 20db apart, respectively. Even though you'll still think that the 90db tone is at a different loudness than the 5000Hz tone.

The end result: The HomePod sounds great at all volumes. Soft, or loud, it sounds natural, balanced, and true to life. For the rest of our testing, we are going to allow the HomePod to do it’s Fletcher-Munson compensation as we do directivity testing and more.

2.e Speaker Design Notes / Insights

Apple is using a 4” high excursion woofer, and 7 BMR’s. According to Apple, the subwoofer, and each tweeter is individually amplified, which Is the correct way to set this up. It also means that Apple had to fit the components for 8 separate amplifiers inside the HomePod, the drivers, electronics, and wifi antenna, all in a very tight space, while keeping electrical interference to a minimum. They did so spectacularly.

It’s really interesting to me that Apple decided to horn-load the Balanced Mode Radiators (BMRs). Balanced Mode Radiators have excellent, predictable dispersion characteristics on their own, and a wide frequency response (reaching from 250Hz to 20kHz, where many traditional tweeters cannot handle anything below 2000Hz). The way Balanced Mode Radiators work, is that BMRs move the flat diaphragm in and out to reproduce the lower frequencies. (just like traditional speakers). However, to produce high frequencies, the flat diaphragm can be made to vibrate in a different way - by rippling (relying on the bending modes to create sound) The term “balanced” comes into play because the material is calibrated to ripple in a very specific way in order to accurately reproduce sound. Here’s a neat gif, Courtesy of Cambridge Audio. Even as it’s rippling, this surface can be pushed in/out to produce the lower tones. The result is a speaker that has great reach across the frequency spectrum, allowing Apple to push the crossover frequency lower, keeping it out of the highly audible range. Here’s a video of a BMR in action for those of you curious to see it up close.

Without tearing open the speaker it’s impossible to verify the BMR apple is using (it may very well be custom) we cannot know for sure what its true properties are, outside of the DSP. It's not possible to separate the two without a destructive teardown. The use of BMR's does seem to explain why the crossover is at a lower frequency - somewhere between 200Hz and 500Hz, which is where the tweeters take over for the subwoofer. We weren’t able to tease out exactly what this was, and it may be a moving target based on the song and the resulting mix created by the DSP. Not much else to say about this.

Even up close, the HomePod shows omnidirectional dispersion characteristics. The differences you might see in the graphs are due to the microphone being directly in front of, or between the BMR’s, and very close to the desk, as I moved it around the HomePod for each measurement.

From just 12” away, the HomePod behaves like a truly Omnidirectional speaker.

2.g HomePod Dispersion/Off Axis 5 ft

Once again, for this one, the HomePod was placed directly on the desk, and not on a makeshift stand. This is for better comparison with the KEF X300A, which I've been using as a desktop bookshelf speaker for 3+ years.

This is the other very important test. For this one, the HomePod was left in place on the desk, but the microphone was moved around the room, from 45º Left to 45º Right, forming an arc with a radius of 5 feet, from the surface of the HomePod.

The dispersion characteristics remain excellent. Apple has demonstrated that not only is the HomePod doing a fantastic job with omnidirectional dispersion, it’s doing all this while compensating for an asymmetrical room. If you look at the floor plan I posted earlier once again, You can see that this room has an open wall on one side, and a closed wall on the other side. No matter. The HomePod handles it exceptionally well, and the frequency response barely changes perceptibly when you walk around the room.

This is the magic of HomePod I was talking about. the room is the sweet spot, and with that, let’s take a look at how HomePod compares to an audiophile grade Bookshelf speaker - namely the KEF X300A, in the same spot, with the same measurements.

2.h KEF X300A Dispersion/Off Axis 5 ft

This is a pretty interesting comparison. The X300A is a 2.0 integrated bookshelf offering from KEF, a famous british speaker design house. Their speakers are known for excellent dispersion characteristics thanks to their concentric Uni-Q drivers. A Uni-Q driver has the tweeter siting in the middle of a woofer, assisted by a waveguide to provide great Off-axis response. The woofer which surrounds the tweeter moves independently, allowing these speakers to put out nice bass. They have a 4.75 inch woofer with a 2” hole cut in the center that sports the wave-guide and tweeter. This is the system I’ve been using at my desk for the better part of 3 years. I love it, and it’s a great system.

As noted in the methods, I used a single KEF X300A unit, sitting directly on the desk, in the very same spot the HomePod sat in, to compare. I tried to match the loudness as closely as possible, too, for good comparisons. Here’s a picture of the setup for measurement..

Another note on the KEFs. They do not use Fletcher Munson loudness compensation. As you can see in this Graph their frequency response does not change as a function of loudness.

While the KEF’s can certainly fill my room with sound, It only sounds great if you’re standing within the 30º listening cone. Outside of that, the response falls of. Here's a measure of the KEF's Directivity. As you can see, while the kef has a remarkably wide dispersion for a typical bookshelf - a testament to the Uni-Q driver array's incredible design. But at 45º Off-axis, there's a noticeable 6db drop in the higher frequencies.

3. The HomePod as a product

The Look and feel is top notch. The glass on top is sort of frosted, but is smooth to the touch. When I first reviewed the home pod, I noted that it was light. I was comparing it with the heft of my KEF speakers. This thing, as small as it is, weighs 5 lbs. Which is quite dense, and heavy for its size. The Fabric that wraps around it is sturdy, reinforced from inside, and feels very good to the touch.

The Frequency response, Directivity, and ability to correct for the room all go to show that the HomePod is a speaker for the masses. While many of you in this subreddit would be very comfortable doing measurements, and room treatment, there is no denying that most users won’t go through that much trouble, and for those users the HomePod is perfect.

Great sound aside, there are some serious caveats about the HomePod. First of all, because of the onboard DSP, you must feed it digital files. So analog input from something like a Phono is out, unless your Phono Preamp has a digital output which can then be fed to the HomePods in realtime via airplay, possibly through a computer. But you cannot give the HomePod analog audio, as the DSP which does all the room correction requires digital input.

Speaking of inputs, you have one choice: AirPlay. which means, unless you’re steeped in the apple ecosystem, it’s really hard to recommend this thing. If you are, it’s a no brainer, whether you’re an audiophile or not. If you have an existing sound system that’s far beyond the capabilities of a HomePod (say, an Atmos setup) then grab a few for the other rooms around the house (Kitchen, bedroom, etc). It’s also a great replacement for a small 2-speaker bookshelf system that sits atop your desk in the study, for example. When this tiny unobtrusive speakers sound so good, and are so versatile, grabbing a few of these to scatter around the house so you can enjoy some great audio in other rooms isn’t a bad move — provided you’re already part of the Apple Ecosystem.

AirPlay is nice. It never dropped out during any of my testing, on either speaker, and provides 16bit 44.1Khz lossless. However, my biggest gripe is hard to get past: There are no ports on the back, no alternative inputs. You must use AirPlay with HomePod. Sure, it’s lossless, but if you’re an android or Windows user, theres no guarantee it’ll work reliably, even if you use something like AirParrot (which is a engineered AirPlay app). I understand that’s deeply frustrating for some users.

As a product, the HomePod is also held back by Siri. Almost every review has complained about this, and they’re all right to do so. I’m hoping we see massive improvements to Siri this year at WWDC 2018. There is some great hardware at play, too. What’s truly impressive is that Siri can hear you if you speak in a normal voice, even if the HomePod is playing at full volume. I couldn’t even hear myself say “Hey Siri” over the music, but those directional microphones are really good at picking it up. Even whispers from across the room while I was facing AWAY from the HomePod were flawlessly picked up. The microphones are scary good — I just hope Apple improves Siri to match. Until then, you can turn just her off, if you don’t care for voice assistants at all.

Stereo is coming in a future update. I cannot wait to see how two HomePods stack up. I may or may not do measurements in the future of such a feature.

4. Raw Data

(This is a zip containing all .mdat files, as well as images used in this review)

5. Bias

Every single reviewer has Bias. Full disclosure: I saw the HomePod before most people. But, I also paid full price for this HomePod, with my own money. I paid for all the equipment to measure it with, and I own every speaker in featured in this review. Neither KEF, nor Apple is paying me to write this review, nor have they ever paid me in the past. At the same time, I’m a huge apple fan. Basically, all the technology I own is apple-related. I don't mind being in their ecosystem, and it’s my responsibility to tell you this.

I hope the inclusion of proper and reproducible measurements, raw data, as well as outlining the procedures followed, will help back the claims made in this writeup. If anyone has doubts, they can easily replicate these measurements with their own calibrated mic and HomePod. Furthermore, I worked with /u/Arve and /u/Ilkless to carefully review this data before posting, so we could explore the capabilities of the HomePod further, and corroborate our conclusions.

6. Acknowledgement / Thanks

This review would not have been possible without /u/Arve and /u/Ilkless lending me some serious help to properly collect and analyze this data. Please thank them for their time and effort. I learned a lot just working with them. Also, shoutout to /u/TheBausSauce for providing some confirmatory measurements with another HomePod. Also, thank you John Mulcahy, for making Room EQ Wizard. Without it, these measurements would not be possible. Finally, I'm deeply saddened by the passing of Jóhann Jóhannsson, the legendary composer. His music is beautiful, so in his memory, please go listen to some of it today. I wish his family the best.

7. Edits

Edit 1: Minor grammar edits

Edit 2: See /u/Arve's really important comment here and graph here for more on Fletcher Munson compensation.

Edit 15: Some really good critique and discussion has been added to the very top of the post.

(5079 W | 29,054 Ch)

8. Shameless plug

Since this is getting tons of attention still, I'm working on launching a Podcast in the coming months. In the comments here, I mentioned "wearing many hats" and my podcast is about personal versatility. If you're interested, You can follow me on various places around the web (listed below) I'll be making an announcement when the Podcast goes live :) Also my inbox is flooded at this point, so if I miss your comments, I apologize.

I'm going to have to sticky something here, since I see it passed around in the Apple-focused press (and since I'm the one who created the graph) by people who don't have experience in measurements:

And here's a look at the Deviation from Linearity between -12 and -24db.

This is not a measure of how flat the frequency response is, and must not be conveyed as such. What the graph actually conveys is how the speaker's response changes between two different loudness levels. It's a useful gauge of how well a speaker handles when being played very loudly.

For those interested, here is how to create that graph for (any) speaker in REW:

Take a measurement at a particular volume setting, let's call this "measurement A"

Without moving the microphone or making any other changes, re-take the same measurement at a different volume setting - "measurement B"

Then add a fixed offset to the least loud measurement, so the graph matches at an anchor point (usually 1 kHz).

Create a new graph by dividing measurement A with measurement B.

What you're then left with is how the frequency response changes when you change the volume.

The ideal for these graphs is for them to be flat, but there will always be some deviation in them, and the one for the HomePod is pretty impressive for a 4" driver.

Yeah I bought mine at a goodwill for $15 a few years ago but it sounds great. They have an aux in so you don’t have to use a 30 pin iPod and blow any other boombox I’ve heard out of the water. Not sure why they would stop making speakers for 12 years, it could have been another solid revenue stream once Bluetooth evolved.

Apple charges a massive licence fee to make iPod/iPhone accessories, and these companies weren’t happy that they were then having to compete with Apple itself.

This is the same reason why Microsoft didn’t make their own PC’s until the Surface range came out. They also intentionally price the Surface high as a as a Halo product, leaving their partners to produce Surface-like devices for much cheaper.

It looks like most people don't care about stereo. Most people aren't aware of soundstage or imaging. Most people don't listen to music while sitting at one location. They have background music while they do stuff around the house. This would be great for that.

Wow, that is quite something. I am now starting to get invested in Apple's ecosystem and also on the lookout for some non-headphone audio gear. If the homepods are really that great with a stereo on the horizon I'll save my money up for that.

One other commenter said that good placement of the speaker is still beneficial. Would you agree? With that in mind, for lower-end audiophiles it still won't be a 'no-brain world' without speaker placement and room treatment.

The only thing it cannot do is Bass below 40hz... but if apple releases a bigger version of the HomePod, they will absolutely take the audio market by a storm.

Until that time someone might ghetto rig something up to send a digital signal to the homepod and the lacking frequencies to a proper subwoofer. But I am certain that Apple will want to get the tech out to market in this version, to get much more testing and more importantly real-world data. That is why a stereo configuration is announced for later and almost certainly a bigger version in the works.

Speaking of headphones above, could you see the technology used to reduce distortion with high excursions being used in headphones, which notoriously have difficulties reproducing bass frequencies?

could you see the technology used to reduce distortion with high excursions being used in headphones, which notoriously have difficulties reproducing bass frequencies?

Absolutely. Since it's a self contained unit, I don't see why not.

One other commenter said that good placement of the speaker is still beneficial. Would you agree? With that in mind, for lower-end audiophiles it still won't be a 'no-brain world' without speaker placement and room treatment.

It's very close to perfect even without proper placement, but it sounds better if you elevate it just a little. It can be as simple as "put this near a wall, and on top of some books". That's all I'd say to someone who was setting it up.

It's very close to perfect even without proper placement, but it sounds better if you elevate it just a little. It can be as simple as "put this near a wall, and on top of some books". That's all I'd say to someone who was setting it up.

Would you advise against placing it next to a computer display, like so?

Ignore the dip below for the two most silent measurements (37 and 25% setting), as it likely is part a fault in how I referenced the loudness, and there may be some measurement error, because you're approaching the room's noise floor and the range where the microphone itself can still be considered calibrated.

The takeaway is that as you lower the volume, it adds bass and treble to create a tonal balance that remains perceptually consistent at all loudness levels.

Some personal notes and observations, based on having stared at these measurements throughout the weekend:

This is an in-room measurement in an untreated room, so do not expect graphs to look as smooth as those from an anechoic chamber or larger measurement space

The Fletcher-Munson compensation is clever, and for a speaker meant for casual use, it's a good idea, but it'd be unsuitable for for instance mixing (which is a moot point anyway, AirPlay latency makes it unsuitable for that anyway)

If you find yourself frequently reaching for volumes where Siri tries to warn you that it's going to be very loud, you should be adding a second HomePod, after which you should be able to have ~103 dB peaks in-room.

Apple could have gone down the route where they made the low-end roll-off a moving target. I'm so glad they didn't. I'm also spooked by the loudness they reach below 100 Hz before the limiter sets in.

Measuring this thing is pretty tough, and I silently curse the fact that Apple haven't launched here in Norway, as I want to do my own battery of tests in a different (and a bit larger) room with different issues

While Apple's automatic room correction algorithms can and should be considered to be witchcraft, it doesn't free the HomePod from proper placement. Ideally, I'd like to see actual speaker stands for them - a trumpet mute-shaped bell that fits in the bottom-shaped indendtation. Make it in brushed aluminum, white and jet black.

My one concern is that max SPL is slightly limited compared to 6-7" monitors. Apple needs to do a HomePod Plus for larger rooms, or people who plan on blasting movies at wall-shaking levels. And while I don't think Apple will ever do it, I'd also love to see a "SubPod"

I hope people are hard at work creating 3D models for HomePod speakers. To me, the sound difference is quite noticeable when on the desk than when slightly elevated due to the internal speaker placement. So yeah, we need some stands!

Reading the review and after having reviewed the data manually (as the raw files were so generously provided), the review sounds over-enthusiastic to me for a number of reasons.

First of all, it is impossible to accurately measure a speaker in a normal room. You need an anechoic chamber if you want good measurement accuracy. If you measure in a normal room then the resulting frequency response incorporates the effect of reflections off walls and furniture. The problem is, the human auditory system does not perceive reflections the same way that a measurement microphone does, because reflections arrive with (relatively long) delays and, most importantly, they arrive at a different angle from the direct sound. A single measurement microphone cannot take that into account, but a human head (with two ears and a brain in the middle) can. For this reason, frequency response measurements made in normal rooms (not anechoic chambers) need to be taken with a huge grain of salt, especially above 1 kHz or so. See Toole, "Sound reproduction: loudspeakers and rooms", chapters 5 & 9 especially, for details.

People who are aware of the above will use impulse response windowing when during the measurements to remove the reflections. This greatly reduces the resolution of the measurement (which is why you really need an anechoic chamber for accurate measurements - there's no such thing as free lunch), but at least the resulting frequency response graph won't be grossly misleading. The experimenter in that Reddit post doesn't even mention windowing anywhere (unless I missed it), which leads to me to suspect that he or she doesn't know what they're doing. It doesn't matter that they took 50 different measurements and providing tons of data: if their procedure is flawed or their interpretation is wrong, the conclusions are garbage. It's like trying to measure the air flow of a fan using tiles of toilet paper of 50 different types: sure you'll get some data, but it's no going to be very informative.

In light of the above, I find it absolutely hilarious that the experimenter is specifying conditions like "Room temperature was 72ºF (22.2ºC) and the humidity outside was 97%. Air Pressure was 30.1 inHg (764.54 mmHg)". It sounds like they've done very rigorous measurements in highly controlled conditions, but that's rendered moot by the overwhelming influence of the specific room in which they made the measurements. It's like trying to weigh two objects using a scale, being very careful to specify the ambient temperature, humidity, pressure and illuminance to the 3rd decimal place, but then neglecting the fact that the measurements are made in zero-g aboard the International Space Station, and then proclaiming with great vigour that the two objects weigh exactly the same. I would invite the experimenter to revise their list of priorities.

The experimenter seems obsessed with that graph which they claim shows a very flat frequency response. They even say, further down the review, that it's an "almost perfectly flat speaker". Mmm. I opened that same measurement in REW and here's what I get (with the same 1/12 octave smoothing as the above image): https://i.imgur.com/3nHZimq.png

Doesn't look as nice doesn't it? That's because of the scale, you see. It's the ages-old trick of messing with the vertical scale to make things look flatter than they really are. In the screenshot that the experimenter posted, the interval between ticks is 10 dB. That's enormous. Almost anything will look almost flat at that scale.

Let me drive that point home by using a similar scale as the one the experimenter used, but this time overlaid with the KEF X300A that the experimented also measured: https://i.imgur.com/8i1oSXW.png

Aside from the bass extension, they look quite similar. Theorem: any frequency response curve will look flat if you zoom out far enough.

When you look more closely, you realize that the Homepod has frequency response irregularities in the range of ±6 dB around its average value over most of the frequency range. If you look at the KEF measurements from the same set, you will find pretty much the same range of variation. And in fact, looking at my own set of measurements of a Genelec 8030A speaker in my own room, I also arrive at a similar number. Does that mean that all these loudspeakers are equally bad? No, of course not. It means that the measurements are corrupted by the influence of the room (see my first point), and that your so-called "data" is garbage. It's like measuring the top speed of a car by driving it at the legal speed limit on the highway, and then pretending that these cars are all equivalent because they can't do more than 120mph. Makes no sense.

Regarding off-axis measurement (dispersion)… aside from, again, the highly dubious value of doing such measurements in a reverberant room, the results are completely unsurprising considering the speaker design. The KEF speaker is a traditional bookshelf speaker that's forward-firing. The HomePod is an omnidirectional design with 7 tweeters facing all directions. Of course the HomePod will show a more consistent off-axis response at wide angles, you don't need to measure anything to arrive at that conclusion. But of course there are tradeoffs involved, otherwise every speaker would use that design. The problem is acoustical interference caused by the sound from the various tweeters interacting with each other, and also from coincident reflection from the back wall. (Maybe Apple's DSP has some magic to work around these issues. Maybe not.) These phenomena are probably occurring in the measurements that the experimenter made, but they're impossible to distinguish from the frequency response "noise" caused by the inadequate measurement protocol (reverberant room).

This paragraph is grossly misleading:

What we can immediately see is that the HomePod has an incredibly flat frequency response at multiple volumes. It doesn’t try to over emphasize the lows, mids, or highs. This is both ideal, and impressive because it allows the HomePod to accurately reproduce audio that’s sent to it. All the way from 40Hz to 20,000Hz it's ±3dB, and from 60Hz to 13.5Khz, it's less than ±1dB... Hold on while I pick my jaw up off the floor.

At first glance it looks like this is about the frequency response of the speaker, and indeed if it was, these would be impressive numbers. It's not, though. It's about deviation from linearity, which has to do mostly with power compression and DSP limiting. It has nothing to do with frequency response, which is a much, much more important metric. The way that passage is worded is so mind-bogglingly misleading that I'm having a hard time believing it was not written that way on purpose.

While I agree with the experimenter that the bass performance of the speaker looks interesting considering its small size, there's some misleading stuff in there too. When the experimenter writes "Apple's got the HomePod competently producing bass down to ~40 Hz, even at 95 dB volumes", that does not mean that the HomePod can produce 95 dB at 40 Hz, which would indeed by extremely impressive for its size. Instead, the linked measurement shows that the HomePod will limit itself to less than ~80 dB at low frequencies. Now the automatic distortion control is interesting perhaps, but still, there's no magic here. (A proper subwoofer can go to 100+ dB at these frequencies, but it's also much larger in size.)

The experimenter mentions that the speaker is capable of room correction. It's not. Proper room correction systems can get frequency response variations down to ±2 dB or less - that's not hard to achieve as it's mostly just about inverting the room response. The experimenter's own measurements, when viewed at the proper scale, show that the HomePod doesn't do any better than the KEF or any other speaker in that regard.

The Fletcher Munson compensation is interesting, but I would need to see some evidence to convince me that such compensation makes for a more "natural" sound at different loudness levels. This compensation does not occur when listening to natural "live" sources, so I wouldn't bet money on it, though I could be convinced either way given appropriate evidence. The experimenter writes as if it's obvious that such loudness compensation is a good thing, but doesn't present any evidence (such as peer-reviewed research, e.g. AES) to back up their claims.

Conclusion: no, these measurements don't show that "The HomePod is 100% an Audiophile grade Speaker", far from it. Because the measurements were made in a reverberant room without windowing, the data is mostly meaningless. The linearity, SPL and distortion measurements are usable to some extent, but these are not the most important criteria when assessing the audio quality of a loudspeaker (unless loud bass is really important for you). Many parts of the "review" are misleading, at times egregiously so, leaving the impression that the experimenter is interpreting the data through Apple-colored glasses.

AFAIK, some anechoic chambers can be rented, so you wouldn't necessarily have to build one (which of course is extremely hard and expensive). If you live near an university campus for example, they might have one and might agree to give you access. YMMV.

I thought one of the points of the way it was measured was to see how the response ended up in a room. It isn’t clear to me what would be accomplished by measuring a speaker that is designed to compensate for in room response in an anechoic chamber. The processing is part and parcel of the performance.

As far as the other critiques I’d like to see the tester respond to those.

Are you sure you don't have one of the "sound enhancer" or equalizer settings on in iTunes? Otherwise, it could just be a volume difference... human ears love even minute volume differences and think they sound better

I had this idea as well but I'm questioning it. If you do this please post how well it works. I'm sure two HomePods in stereo will sound great with iTunes music streaming, but since they are AirPlay only, how will they work with anything that is not Apple sourced (YouTube, Twitch, Chrome, VLC, etc)? I know AirFoil exists, but with the latency issues, I don't know if these can function as true computer speakers, even though I wish they could.

My problem is the requirement for internet access, at least it is required as I understand it today. That makes the unit less than ideal for travel where you might not always have internet access. Think camping or remote hotels.

I need to research this a bit more in the hopes that it can be used over WiFi without actual internet access.

On the "Home" tab in the Home app, in the upper left corner, there is an icon that looks like location services (the gps arrow). Tap on it and it takes you to the settings for your home, and you can change how speaker access is handled.

It defaults to "anyone on the network", so I'd expect that if there is no network then no one can AirPlay to it. However, you can change it to "everyone" (and set a passcode if you're sane) to let people who aren't on your WiFi network AirPlay to it.

I wonder if, after changing that setting, you can do peer-to-peer AirPlay with no WiFi network? I'd test mine, but my roommates probably wouldn't appreciate me unplugging the router...

Oh, yeah, and as /u/zdude1858 pointed out, the AirPlay sender has to support peer-to-peer WiFi, which older Macs often don't.

I wouldn't expect Siri to work. As for the WiFi network the issue there is loss of the connection to the internet. Think riding around the country in an RV which sometimes has access to a hotspot and sometimes not.

Probably not. :3 There is a ton of technical know-how when it comes to understanding what's going on. I'm hoping that once people get through it, we'll see some more discussion, as well as people asking questions.

I’m no audiophile, but I’ll shoot for an ELI5:
HomePod can play a wide frequency of sounds consistently, where a cheaper, shittier speaker would not. Shockingly, this is consistent regardless of the speaker’s placement within a space, the loudness of the speaker, or where you’re standing relative to it.

How is this not getting more attention? Those graphs are insanely misleading. 5-140db with 1/12 smoothing is criminal. The midrange isn't that terrible, but it's nowhere near flat. The midbass looks fucking horrible though.

Very much so, I'm not in the audiophile world yet, my best speaker is a cheap logitech. But I am in the Apple ecosystem and use Apple Music, I think the HomePod would be the perfect introduction to the brave(expensive) new world.

In your Directivity Measurements graph for the HomePod, both times that you were off axis to the left measured higher than 0 degrees both times you were off axis to the right measured lower than 0 degrees. Did you measure left/right from the speaker's point of view? Is it possible that, due to the shape of the room, that is done on purpose by the speaker? Your room isn't symmetrical, so you would think that the HomePod, if it is doing what Apple suggests, would output audio in a non-symmetrical way as well.

That's my guess as to what's going on. It's one of the reasons that I made note of the room geometry.

Did you measure left/right from the speaker's point of view?

I wanted to do that, as it's the way we do things in medicine, but I figured it would confuse people. The L and R measurements are from the perspective of a person facing the desk. So measurements marked with an R will be near the wall, and measurements marked with L are near the partial wall/open space. So it makes sense the HomePod was louder on the Left side, compensating for lack of a wall. Just more DSP in action.

However, when I play music through it, what it appears to be doing is using the 2-channel information, and what it knows about the room to pick what tweeters certain parts of the mix go to. So, yes, it does pick some parts of the mix to bounce off the wall, but not the whole mix.

If reddit wants to crowdfund a Google Home Max review... I could do it... but not until 5 weeks from now. My weekends are booked. But seriously, I'd be down to take a similar approach to the Google Home Max.

Total noob question and i skim read the testing procedure, so please go easy on me. I was looking at the design of the Homepod which seems to have an upfiring speaker and then smaller speakers shooting outwards in a circle. Compare this to the single KEF speaker which is a point source speaker facing forward for your tests.

Your test spots are in a circular position around the Homepod, seemingly more in line with the Homepods outward firing speakers. The upward firing speaker than providing even sound across all measuring positions as it is not directly in line with a pick up spot.

Would it not be fairer than, to sit the KEF speaker on its back, also shooting upwards to give an even spread of sound, rather than the forward firing point source?

It just seems that the test and measurement points will always favor an omni-directional speaker.

So, the best way to measure each speaker is by positioning it the way it was meant to be listened to in a room.

For the HomePod, it was designed to have that up firing woofer, whereas the Kef's sound their best when you're sitting in front of them. Turning the KEF on its back to measure.

The Mic was the same distance from the speaker in all cases, and each speaker was in the same position in the room overall. These conditions don't favor one over the other - the measurements made were the same, and the equipment doing all the work was the same.

If you were to fire that kef speaker upward it would measure considerably worse. Remember how the 45º Off-axis response was showing a roll-off? Having the KEF speaker firing upward, while measuring from the side would be as bad as taking a 90º off-axis response... it would measure awful, and sound awful.

It seems that the test conditions favor an omnidirectional speaker, because omnidirectional speakers are just that much better than traditional point-source drivers.

In a typical speaker review, you'd see these same measurements done between two point source speakers, and we'd be talking about how one sounds better at 30º and the other manages great sound at 40º off-axis.

I'm so excited for where speakers are going right now. From the BeoPlay90 to the Kii Three to the Apple HomePod. The convergence of technology to correct for the room at the device level is absolutely what the millennial generation is going to demand from premium Audio going forward.

The bar has been set. Bravo.

(I did return a homepod. I'm an EDM guy and demand a certain performance to 20hz, which homepod lacks. It sounds great and I hope there is a stereo 2.1 option in the near future.)

Here’s an interesting read about their acoustic team and audio lab. With the former head of B&W engineering I’m sure they have done their homework. I have a feeling this is only the beginning of more serious audio products from Apple.

Holy shit. I guess this is why you shouldn’t take preemptive shits on a company’s speaker when the company a.) hired the guy who literally invented some of the most impressive theater speaker / DSP tech ever and b.) has more money to devote to such a product than literally everyone else.

I honestly wonder how they compare to my Q300's. At the same time, I wonder if comparing these to passive speakers with (probably) a much better amp/dac than the X300A would affect your conclusion, like the Q100s or Q300s. Also, I an wondering if it is anywhere close to being worth the price.

Note: I do not own any Apple products, and don't see myself buying them anytime soon. I have been reading reviews like where people are saying "Apple has reinvented the speaker...blah..blah". Generally I have a negative bias towards Apple products, but if it is any good, I am considering getting one for my mom who is kinda illiterate (in my view as a complete geek) in the world of tech.

Well, the X300A has an onboard Class D and Class A bi-amp, each one individually coupled to each driver. It's got a solid DAC in there, too.

The measurements speak for themselves. A lot of people, especially in this subreddit, were extremely dismissive of the HomePod because it's an apple product. The measurements have made many of them reconsider.

It's hard to say how they'd stack up against the Q300, or Q100's... but if you were to take measurements of your own speakers, you could do the comparison yourself, in REW, since I've made all the data available.

I think that if the fact that this product is virtually exclusive to the Apple ecosystem is true, it should really be mentioned before the enormous review. I was sold on the device 20 paragraphs in before I realised in the conclusion that there was no way to make analog connection to it, as I'm totally new to the product...

I played with one today at my local Best Buy and I was not impressed at all with the audio - it certainly seemed balanced top to bottom and had decent bass for the size, but dynamics were gone, and there was no way for it to produce any sort of soundstage or imaging with a single speaker on a table in a store. I’m guessing that a lot of this is because of the environment, being out on the showroom floor. I’ll need to hear one in a different room. I’m thinking that two of these and a sub would be pretty good for the price.

Is the foam insulating the sound, or elevating it away from the reflective surface? Basically, should I be looking for a sort of pillar that the HomePod should clear, acoustically, or just a rectangle to cover the reflective surface?

It's some of both. The foam absorbs some of the sound but also puts more distance from the speaker to the table, so when reflections do happen, they have far less energy (basically, inverse square law).

Happened to see this comment and glad I did. My wife has just such a block and I thought of using it, but was like “wait, should I put a speaker on foam?”... was worried about some kind of dampening effect that would mess things up. But I guess not?

Nice writeup! I picked one up Friday at a local Apple Store and I'm really impressed with the sound. And, as others have said, the microphones are insanely sensitive. It's really, really amazing. I do wish Siri was better, but she's been good enough, at least.

The back of the napkin math I did indicates 98 dB above 100 Hz (The limiter that protects the bass driver from literally blowing up limits the volume a bit more for the deep bass).

While bigger speakers may go a little louder, this is well inside "uncomfortably loud" territory, in particular if you add a second HomePod to do stereo, and it's almost certainly louder than you'll ever want to listen if you want to keep your hearing.

Trying to decide between a Klipsch The Three or a HomePod, and I’m a little less on the fence about the HomePod, but can’t help but wonder if I might be more satisfied with the sound quality of the Three.

Any thoughts on the spend required to create a similar quality audio experience to the HomePod with other speaker/amp products? At what price point would the HomePod audio quality sit in the rest of the market?

Thanks for writing the first technical review of this device! I don't understand why Apple hasn’t led with this material in marketing through high end audio publications. The technical achievement is astonishing.

It sounds bass heavy because most small speakers do not produce accurate bass - they under-deliver. If that's what youve been hearing your whole life, it's going to feel like a lot of bass. Our experiences are relative -- if you put your hand it cold water, then warm water, it'll feel warm. Put your hand in hot water, and then put it in warm water, and the water will feel cold.

just wanna say i got my homepod last friday.. i can basically loudly say "hey siri" from a different room, probably 30 feet away with walls in the way while it is BLASTING music and it hears me. it literally is freaking me out. the sound is incredible. nothing distrorts, bass is rich and deep - better than some 10" subs i've heard. siri sounds like he/she/they are right next to you talking. i take calls on it, i used it to joke with my girlfriend when we were just laying down.. just said "hey siri, play some berry white" and 'it was on' if you get what i did there. it feels like the future. idk why. if there's one negative it's the price, because i'm getting another and suddenly a nice little $350 is a hefty almost $800.

"Let me show you about emai... oh no service, yeah duh. Well I can show you this video... oh was from the cloud i guess. Well I can show you this game that's pretty neat. Hmm 29% battery left... do you guys have a mini usb?"

Full disclosure, I didn't know the HomePod was a new product and I thought you were talking about those really shitty docks for iPods and iPhone way back when. I just thought this was an amazing shitpost for a solid 5 minutes.

Don't own any apple products but this might be the thing that set me down that fruit path.

Will homepods 40hz get me that fat, smooth, dense sound of a true concert bass drum in orchestral works?

Or a huge but transparent sounding organ (think Resphigis' Pines of Rome, second movement, when the freaking shit hits the fan and the organ, bass drum, basses all hit. Also the part in fantasisa 2000 where the whales freaking fly. God damn I love that part.

I’ve heard this against a well setup stereo pair of $1k speakers and while these measurements are impressive, the HomePod cannot touch them in providing a holographic feeling soundstage and accurate placement of instruments within. If that is your thing.... :-)